1. Field of the Invention
The present invention relates to a light beam scanner and, more particularly, to the light beam scanner of a light beam recording system for recording information such as letters in a recording medium by scanning a light beam.
2. Description of the Related Art
As a light beam scanning system for recording information such as letters in a recording medium with a light beam, there is known (in Japanese patent application Laid-Open No. 55 - 67722) a laser computer output microfilmer (which will be shortly referred to a "Laser COM") for recording information such as letters directly in a recording medium such as heat mode recording medium, e.g., a laser direct recording film (LDF) by scanning a laser beam which is modulated on the basis of the output information of a computer, for example. The Laser COM has its light beam scanner constructed of: a rotary polygon mirror for deflecting the laser beam, which is emitted from an argon laser and modulated in accordance with the letter information or the like, in a main scanning direction; and a galvanometer having a deflecting mirror for deflecting the light reflected from the rotary polygon mirror in an auxiliary scanning direction, so that the letter information or the like may be recorded by scanning the recording medium with the laser beam through a scanning lens by the rotary polygon mirror and the galvanometer.
However, the light beam scanner using the rotary polygon mirror and the galvanometer is troubled by a problem that its accuracy is degraded with time due to the wear or the like of a moving part. On the other hand, the rotary polygon mirror is turned at a constant speed by a motor to deflect the laser beam in the main scanning direction so that the mirror face is inclined due to the inclination or the like of the shaft of the motor. The inclination of the mirror face causes irregular scans in the auxiliary direction. In order to prevent the irregular scanning, a correcting optical system is required, and consequently another problem that the light beam scanner is large-sized occurs.